Bind the diagnostics server on ipv4 ports.

pkg/analysis_server/lib/src/server/http_server.dart

Index: pkg/analysis_server/lib/src/server/http_server.dart
diff --git a/pkg/analysis_server/lib/src/server/http_server.dart b/pkg/analysis_server/lib/src/server/http_server.dart
index 50da1549ea1ae6eaa19a72fba35f568063ae9eea..8f144112c75c74bb2bf0fb28b2a71982999c56d5 100644
--- a/pkg/analysis_server/lib/src/server/http_server.dart
+++ b/pkg/analysis_server/lib/src/server/http_server.dart
@@ -79,7 +79,7 @@ class HttpAnalysisServer {
 
     try {
       _serverFuture =
-          HttpServer.bind(InternetAddress.LOOPBACK_IP_V6, initialPort ?? 0);
+          HttpServer.bind(InternetAddress.LOOPBACK_IP_V4, initialPort ?? 0);
 
       HttpServer server = await _serverFuture;
       _handleServer(server);